In an attempt to deliver drugs to the liver, various studies on liposome preparations have been conducted. Inter alia, the report by Surolia et al. in B.B.A., 497, 760-765 (1977), Japanese Patent Application (OPI) No. 98121/80 (the term "OPI" as used herein means "unexamined published patent application") and the report by Scherphof et al. in B.B.A., 734, 40-47 (1983) are known as studies on delivering of liposome preparations to the liver parenchymal cells.
In case of these prior art techniques, the liposomal lipid membrane contains naturally-occurring substances, such as asialoganglioside, digalactosyl diglyceride, lactosylceramide, etc., in order to deliver the liposomes to the liver parenchymal cells. It is difficult, however, to produce liposomes containing such naturally-occurring substances in the lipid membrane thereof on an industrial scale, though possible in laboratories, because of the difficulty in production of these naturally-occurring substances in a large quantity on an industrial scale.